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28205 = 55641
BaseRepresentation
bin110111000101101
31102200122
412320231
51400310
6334325
7145142
oct67055
942618
1028205
111a211
12143a5
13cab8
14a3c9
158555
hex6e2d

28205 has 4 divisors (see below), whose sum is σ = 33852. Its totient is φ = 22560.

The previous prime is 28201. The next prime is 28211. The reversal of 28205 is 50282.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21316 + 6889 = 146^2 + 83^2 .

It is not a de Polignac number, because 28205 - 22 = 28201 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2816 + ... + 2825.

It is an arithmetic number, because the mean of its divisors is an integer number (8463).

228205 is an apocalyptic number.

It is an amenable number.

28205 is a deficient number, since it is larger than the sum of its proper divisors (5647).

28205 is an equidigital number, since it uses as much as digits as its factorization.

28205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5646.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 28205 is about 167.9434428610. The cubic root of 28205 is about 30.4398168247.

Adding to 28205 its reverse (50282), we get a palindrome (78487).

The spelling of 28205 in words is "twenty-eight thousand, two hundred five".

Divisors: 1 5 5641 28205